Ruthenium-phosphine complex

ABSTRACT

A ruthenium-phosphine complex having a 2,2&#39;-bis(diphenylphosphino)-1,1&#39;-binaphthyl or its derivative as a ligand and carboxyl groups bonded to the ruthenium atom thereof is disclosed. The complex is inexpensive and exhibits excellent performances as a catalyst for various organic syntheses, and particularly for asymmetric hydrogenation.

FIELD OF THE INVENTION

This invention relates to a ruthenium-phosphine complex useful as acatalyst for various organic syntheses, and particularly for asymmetrichydrogenation.

BACKGROUND OF THE INVENTION

Various transition metal complexes have hitherto been employed ascatalysts for organic syntheses, and intensive studies have beenconducted on syntheses using noble metal complexes as catalysts takingadvantages of their stability and easiness in handling though they areexpensive. In particular, studies have been directed to asymmetriccatalysts to be used in asymmetric syntheses, such as asymmetricisomerization, asymmetric hydrogenation, and the like. Of the reportedasymmetric catalysts, metal complexes formed between an olefinic rhodiumcomplex and an optionally active tertiary phosphine are especially wellknown. Such complexes typically include a rhodium-phosphine complexusing 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (hereinafterabbreviated as BINAP) as a ligand as disclosed in Japanese PatentApplication (OPI) No. 61937/80 (the term "OPI" as used herein means"unexamined published application"). One example of application isdescribed in Inoue et al., Chemistry Letters, pp. 1007-1008 (1985), inwhich they obtained citronellol by asymmetric hydrogenation of geraniolor nerol using various rhodium-phosphine catalysts in an optical yieldof 66%.

On the other hand, known ruthenium complexes, though there are not somany reports as compared with rhodium complexes, include those havingBINAP or 2,2'-bis(di-p-tolylphosphino)-1,1'-binaphthyl (hereinafterabbreviated as T-BINAP) as a ligand, i.e., Ru₂ Cl₄ (BINAP)₂ (NEt₃)(wherein Et represents an ethyl group, hereinafter the same) and Ru₂ Cl₄(T-BINAP)₂ (NEt₃), as reported in Ikariya et al, J. Chem. Soc., Chem.Commun., pp. 922 (1985). However, the state-of-the-art rutheniumcomplexes are not satisfactory in stability as well as asymmetric yield.

Although metallic rhodium provides excellent complex catalysts, it isexpensive due to limitations in place and quantity of production. Whenused as a catalyst component, it forms a large proportion in cost of thecatalyst, ultimately resulting in increase in cost of the finalcommercial products. While metallic ruthenium is cheaper than rhodiumand appears promising as a catalyst component for industrialapplication, it still has problems in its activity to cope withprecision reactions and its range of application.

Therefore, it has been keenly demanded to develop a catalyst which isinexpensive, has high activity and durability, and catalyzes asymmetricreactions to attain high optical yields, i.e., to produce reactionproducts having high optical purity.

SUMMARY OF THE INVENTION

As a result of extensive investigations with the purpose of meeting theabove-describe industrial demand, the inventors have discovered a novelruthenium complex having high catalytic activity, which is usable eitherfor general syntheses when the ligand thereof is optically inactive orfor asymmetric syntheses when the ligand thereof is optically active.

The present invention relates to a ruthenium-phosphine complex in whichcarboxyl groups are bonded to a ruthenium atom, which is represented byformula (I) ##STR1## wherein X represents a hydrogen atom, an aminogroup, an acetylamino group, or a sulfo group; R represents a hydrogenatom or a lower alkyl group (e.g., those having from 1 to 4 carbonatoms); R₁ and R₂ each represents an alkyl group (e.g., those havingfrom 1 to 9 carbon atoms), a halogenated lower alkyl group (e.g., thosehaving from 1 to 4 carbon atoms; examples of the halogen includefluorine, chlorine, and bromine), a phenyl group, a phenyl groupsubstituted with a lower alkyl group (e.g., those having from 1 to 4carbon atoms), an α-aminoalkyl group (e.g., those having from 1 to 4carbon atoms), or an α-aminophenylalkyl group (e.g., those having from 7to 10 carbon atoms), or R₁ and R₂ are taken together to form an alkylenegroup (e.g., those having from 1 to 4 carbon atoms); and n represents 1or 2.

DETAILED DESCRIPTION OF THE INVENTION

For the sake of brevity, the BINAP derivative moiety in formula (I) asrepresented by formula ##STR2## will be hereinafter represented by "L".

The novel ruthenium-phosphine complex of formula (I) according to thepresent invention can be prepared from Ru₂ Cl₄ (L)₂ (NEt₃) as a startingcompound.

The starting compound, Ru₂ Cl₄ (L)₂ (NEt₃), can be obtained by theprocess disclosed in Japanese Patent Application (OPI) No. 63690/86(corresponding to European Pat. No. 174,057A). Of the starting materialsL used herein, those having a sulfo group or an amino group as X can beprepared easily by sulfonation, or nitration followed by reduction, ofBINAP, etc., respectively, in a known manner. L in which X is anacetylamino group can be obtained by acetylation of those wherein X isan amino group.

In the preparation of the ruthenium-phosphine complex of the invention,Ru₂ Cl₄ (L)₂ (NEt₃) and a carboxylic acid salt are reacted in an alcoholsolvent such as methanol, ethanol, t-butanol, etc. at a temperature offrom about 20° to about 110° C. for a period of from 3 to 15 hours.After the solvent is removed by distillation, the desired complex isextracted with a solvent such as diethyl ether, ethanol, etc., and theextract is evaporated to dryness to obtain a crude complex. Theresulting crude complex as produced may be used directly as a catalystfor asymmetric hydrogenation or the like reaction, or it may be purifiedby recrystallization from ethyl acetate, and the like.

Ruthenium-phosphine complexes having any carboxyl group introduced canbe obtained by varying the kind of carboxylic acid salt used. Specificexamples of the carboxylic acid salts which can be used are sodiumacetate, sodium propionate, potassium acetate, silver acetate, sodiumbutyrate, sodium isobutyrate, sodium monochloroacetate, sodiumdichloroacetate, sodium tri-chloroacetate, sodium nonylate, sodiumbenzoate, sodium p-methylbenzoate, sodium glutarate, sodium octylate,sodium adipate, sodium phthalate, glycine sodium salt, alanine sodiumsalt, phenylalanine sodium salt, valine sodium salt, leucine sodiumsalt, isoleucine sodium salt, etc.

Complexes of formula (I) having a trifluoroacetate group are obtained byreacting a diacetate complex of formula (I), Ru(L)(O₂ CCH₃)₂, asprepared by the abovedescribed process with trifluoroacetic acid inmethylene chloride as a solvent at about 25° C. for about 12 hours.

Complexes of formula (I) wherein a 2-equivalent L is coordinated to aruthenium atom are obtained by reacting RuHCl(L)₂ (obtainable by theprocess disclosed in Japanese Patent Application (OPI) No. 63690/86)with a carboxylic acid salt in a solvent such as methylene chloride.

When an optically active L is used, ruthenium-phosphine complexes havingcorresponding optically active carboxyl groups bonded thereto can beobtained.

The thus obtained ruthenium-phosphine complex of formula (I) accordingto the present invention has excellent performance properties as acatalyst for asymmetric hydrogenation or the like reaction. For example,when the complex is applied to asymmetric hydrogenation of allylalcohols such as geraniol and nerol, it exhibits very high catalyticactivity even at room temperature. In some detail, the reaction ofgeraniol rapidly proceeds in the presence of the complex at a molarconcentration of from 1/5000 to 1/50000 based on the geraniol as asubstrate to yield a hydrogenation product, i.e., citronellol, at aselectivity reaching almost 100%. The resulting citronellol has anoptical purity of from 96 to 98%. To the contrary, the aforesaid knownruthenium complexes described in Japanese Patent Application (OPI) No.63690/86 are less sufficient in stability, selectivity to citronellol,and solubility in a substrate than the complexes of the invention. Inparticular, the selectivity to citronellol achieved by the conventionalruthenium complexes is so low that the reaction is accompanied byformation of, as a by-product, dihydrocitronellol having 2 mols ofhydrogen added to geraniol or nerol depending on the reactionconditions.

The present invention will now be illustrated in greater detail by wayof Examples and Use Examples, but it should be understood that thepresent invention is not limited thereto. In these examples, all thepercents are by weight unless otherwise indicated.

EXAMPLE 1 Preparation of Ru((-)--BINAP)(O₂ CCH₃)₂([2,2'-Bis(diphenylphosphino)-1,1'-binaphthyl]ruthenium-diacetate)

In a 250 ml-volume Schlenk-tube were placed 1.43 g (0.9 mmol) of an Ru₂Cl₄ ((-)--BINAP)₂ (NEt₃) complex which was prepared by the process ofJapanese Patent Application (OPI) No. 63690/86 and 3.06 g (37 mmol) ofsodium acetate. After the atmosphere was thoroughly displaced withnitrogen, 100 ml of t-butanol was added thereto, followed byheat-refluxing for 12 hours. After completion of the reaction, thet-butanol was removed by distillation under a reduced pressure of 20mmHg, and the residual solid was extracted twice with 10 ml portions ofdiethyl ether. The diethyl ether was distilled off to dryness, and theresulting solid was further extracted twice with 10 ml portions ofethanol. The extract was concentrated to dryness to obtain 1.5 g ofcrude Ru((-)--BINAP)(O₂ CCH₃)₂. Recrystallization from ethyl acetategave 0.79 g (yield: 54%) of a yellowish brown solid having a meltingpoint of 180° to 181° C. (with decomposition).

Elemental Analysis for C₄₈ H₃₈ O₄ P₂ Ru:

    ______________________________________                                                  Ru   P           C      H                                           ______________________________________                                        Found (%):  11.85  7.28        68.35                                                                              4.61                                      Calcd. (%): 12.01  7.36        68.48                                                                              4.55                                      ______________________________________                                    

The results of instrumental analyses are as follows. The ¹ H nuclearmagnetic resonance spectrum (¹ H NMR) was determined with a model ofJNM-GX400 (400 MHz) manufactured by JEOL Ltd., and the chemical shiftwas determined using tetramethylsilane as an internal standard. The ³¹ Pnuclear magnetic resonance spectrum (³¹ P NMR) was determined with amodel of JNM-GX 400 (161 MHz) manufactured by JEOL LTd., and thechemical shift was determined using 85% phosphoric acid as an externalstandard.

³¹ P NMR (CDCl₃) δ ppm: 65.00 (s)

¹ H NMR (CDCl₃) δ ppm: ##STR3##

EXAMPLE 2 Preparation of Ru((-)--BINAP)(O₂ CCF₃)₂([2,2'-Bis(diphenylphosphino)-1,1'-binaphthyl]ruthenium-ditrifluoroacetate

0.46 g (0.51 mmol) of Ru((-)--BINAP)(O₂ CCH₃)₂ as prepared in Example 1was precisely weighed out and placed in a Schlenk-tube with itsatmosphere having been replaced with nitrogen. The content was dissolvedin 5 ml of oxygen-free methylene chloride to form a uniform solution. Tothe solution was added 0.09 ml (1.15 mmol) of trifluoroacetic acidhaving been purified by distillation, followed by stirring at roomtemperature for 12 hours. After completion of the reaction, the reactionmixture was concentrated to dryness to obtain 0.6 g of a crude complex.The resulting complex was dissolved in 1 ml of toluene, and 5 ml ofhexane was added thereto in small portions. The mixture was allowed tostand at room temperature overnight, and the precipitated solid wascollected by filtration and dried under reduced pressure (0.2 mmHg) for10 hours to obtain 0.339 g (yield: 70%) of a purified complex. Theresulting complex was identified to be Ru((-)--BINAP)(O₂ CCF₃)₂ from theresults of elemental analysis and instrumental analyses.

Elemental Analysis for C₄₈ H₃₂ F₆ O₄ P₂ Ru:

    ______________________________________                                                  Ru   P           C      H                                           ______________________________________                                        Found (%):  10.47  6.43        60.89                                                                              3.57                                      Calcd. (%): 10.64  6.52        60.7 3.40                                      ______________________________________                                    

³¹ P NMR (CDCl₃) δ ppm: 63.016

¹ H NMR (CDCl₃) δ ppm: 6.1-8.2 (m, 32H)

EXAMPLE 3 Preparation of Ru((-)--T-BINAP)₂ (O₂ CCH₃)₂(Bis[2,2'-bis(di-p-tolylphosphino)-1,1'-binaphthyl]ruthenium-diacetate)

0.45 g (0.3 mmol) of RuHCl((-)--T-BINAP)₂ synthesized by the process ofJapanese Patent Application (OPI) No. 63690/86 and 0.11 g (0.66 mmol) ofsilver acetate were precisely weighed out and placed in a Schlenk-tube,and 5 ml of oxygen-free methylene chloride was added thereto, followedby stirring at room temperature for 12 hours. After completion of thereaction, the reaction mixture was filtered through Celite under anitrogen stream. The filtrate was concentrated to dryness to obtain 0.57g of a crude complex. The resulting complex was dissolved in 1 ml oftoluene, and 5 ml of hexane was slowly added thereto. The precipitatedsolid was collected by filtration under a nitrogen stream and driedunder reduced pressure (0.5 mmHg) at room temperature to obtain 0.246 g(yield: 52%) of a purified complex. This complex was identified to beRu((-)--T-BINAP)₂ (O₂ CCH₃)₂ by the results of elemental analysis andinstrumental analyses.

Elemental Analysis for C₁₀₀ H₈₆ O₄ P₄ Ru:

    ______________________________________                                                  Ru   P           C      H                                           ______________________________________                                        Found (%):  6.30   7.53        76.85                                                                              5.57                                      Calcd. (%): 6.41   7.86        76.18                                                                              5.50                                      ______________________________________                                    

³¹ P NMR (CDCl₃) δ ppm: 63.79

¹ H NMR (CDCl₃) δ ppm: ##STR4##

EXAMPLES 4 TO 17

Complexes were prepared in the same manner as in Examples 1, 2, or 3except for replacing the respective L and carboxylic acid salt withthose shown in Table 1. The preparation was in accordance with Example 1for Examples 4 to 7, 9 to 13, 15, 16, and 17; Example 2 for Example 8;and Example 3 for Example 14, respectively.

In Table 1, the following abbreviations are used.

    ______________________________________                                        t-Bu:        t-Butyl group                                                    i-Pr:        Isopropyl group                                                  Ph:          Phenyl group                                                     BINAP:       2,2'-Bis(diphenylphosphino)-1,1'-                                             binaphthyl                                                       T-BINAP;     2,2'-Bis(di-p-tolylphosphino)-1,1'-                                           binaphthyl                                                       t-BuBINAP:   2,2'-Bis(di-p-t-butylphenylphosphino)-                                        1,1'-binaphtyl                                                   sulfonated   2,2'-Bis(diphenylphosphino)-5,5'-bis-                            BINAP:       (sodium sulfonate)-1,1'-naphthyl                                 amino        2,2'-Bis(diphenylphosphino)-5,5'-bis-                            BINAP:       (amino)-1,1'binaphthyl                                           acetylamino  2,2'-Bis(diphenylphosphino)-5,5'-bis-                            BINAP:       (acetylamino)-1,1'-binaphthyl                                    ______________________________________                                    

                                      TABLE 1                                     __________________________________________________________________________    Example                   Elemental Analysis (%)                                                                     .sup.31 P NMR                                                                      .sup.1 H NMR                      No.  Complex              Element                                                                            Found                                                                             Calcd.                                                                            δ Value                                                                      δ Value                     __________________________________________________________________________    4    Ru((-)-BINAP)(O.sub.2 Ct-Bu).sub.2                                                                 Ru   10.63                                                                             10.91                                                                             65.542 (s)                                                                         0.895 (s, 18H)                         (for C.sub.54 H.sub.50 O.sub.4 P.sub.2 Ru)                                                         P     6.58                                                                              6.69    6.4-7.8 (m, 32H)                                            C    70.32                                                                             70.04                                                                H     5.67                                                                              5.44                                      5    Ru((-)-BINAP)(O.sub.2 CPh).sub.2                                                                   Ru   10.14                                                                             10.46                                                                             65.601 (s)                                                                         6.3-8 (m, 42H)                         (for C.sub.58 H.sub.42 O.sub.4 P.sub.2 Ru)                                                         P     6.33                                                                              6.41                                                                C    72.30                                                                             72.12                                                                H     4.56                                                                              4.38                                      6    Ru((-)-TBINAP)(O.sub.2 CCH.sub.3).sub.2                                                            Ru   11.06                                                                             11.26                                                                             63.215 (s)                                                                         1.77 (s, 3H)                           (for C.sub.52 H.sub.46 O.sub.4 P.sub.2 Ru)                                                         P     6.76                                                                              6.90    1.84 (s, 3H)                                                C    69.68                                                                             69.56    2.38 (s, 12H)                                               H     5.33                                                                              5.16    6.2-7.8 (m, 28H)                        ##STR5##            Ru P C H                                                                            9.98  6.07 72.64  4.89                                                           10.17  6.23 72.50  4.66                                                           65.055 (s)                                                                         2.3 (s, 6H) 6.4-8.3 (m, 40H)      8    Ru((-)-TBINAP)(O.sub.2 CCF.sub.3).sub.2                                                            Ru    9.89                                                                             10.05                                                                             59.910                                                                             2.351 (s, 12H, CH.sub.3)               (for C.sub.52 H.sub.40 F.sub.6 O.sub.4 P.sub.2 Ru)                                                 P     5.82                                                                              6.16    5.8-8.1 (m, 28H)                                            C    62.27                                                                             62.09                                                                H     4.15                                                                              4.01                                      9    Ru((-)-TBuBINAP)(O.sub.2 CCH.sub.3).sub.2                                                          Ru    9.27                                                                              9.48                                                                             62.073                                                                             1.26, 1.24, 1.22,                      (for C.sub.64 H.sub.70 O.sub.4 P.sub.2 Ru)                                                         P     5.64                                                                              5.81    1.17 (s, 9H for each)                                       C    72.26                                                                             72.09    1.84 (s, 6H)                                                H     6.74                                                                              6.62    6.4-7.8 (m, 28H)                  10   Ru((+)-amino BINAP)(O.sub.2 CCH.sub.3).sub.2                                                       Ru   11.43                                                                             11.59                                                                             63.174                                                                             1.88 (s, 6H)                           (for C.sub.48 H.sub.40 N.sub.2 O.sub.4 P.sub.2 Ru)                                                 P     6.97                                                                              7.11    3.24 (s, 4H)                                                C    66.30                                                                             66.13    6.20-7.50 (m, 30H)                                          H     4.73                                                                              4.62                                                                N     3.24                                                                              3.21                                      11   Ru((+)-acetylamino BINAP)                                                                          Ru   10.44                                                                             10.57                                                                             63.832                                                                             1.92 (s, 6H)                           (O.sub.2 CCH.sub.3).sub.2                                                                          P     6.35                                                                              6.48    2.61 (s, 6H)                           (for C.sub.52 H.sub.44 N.sub.2 O.sub.6 P.sub.2 Ru)                                                 C    65.48                                                                             65.34    6.75-7.75 (m, 32H)                                          H     4.79                                                                              4.64                                                                N     2.97                                                                              2.93                                      12   Ru((+)-sulfonated BINAP)-                                                                          Ru    9.83                                                                              9.66                                                                             61.524                                                                             1.95 (s, H)                            (O.sub.2 CCH.sub.3).sub.2                                                                          P     6.11                                                                              5.92    6.75-8.7 (m, 30H)                      (for C.sub.48 H.sub.36 O.sub.10 P.sub.2 RuNa.sub.2 S.sub.2)                                        C    55.03                                                                             55.12                                                                H     3.35                                                                              3.47                                      13                                                                                  ##STR6##            Ru P C H                                                                           11.69   7.13 69.05  4.57                                                          11.84  7.26 68.93  4.49                                                           61.61 61.47                                                                        1.20-2.45 (m, 6H) 6.30-7.90                                                   (m, 32H)                          14   Ru((-)-TBINAP).sub.2 (O.sub.2 CCF.sub.3).sub.2                                                     Ru    5.92                                                                              6.00                                                                             61.48                                                                              2.35, 2.48 (s, 12H for each)           (for C.sub.100 H.sub.48 O.sub.4 F.sub.6 P.sub.4 Ru)                                                P     7.28                                                                              7.35    6.20-7.80 (m, 56H)                                          C    71.48                                                                             71.30                                                                H     4.85                                                                              4.79                                      15                                                                                  ##STR7##            Ru P C H                                                                            9.47  5.65 70.94  5.17                                                            9.61  5.89 70.78  4.98                                                           50.52                                                                              2.50-3.10 (m, 10H) 6.20-7.90                                                  (m, 42H)                          16                                                                                  ##STR8##            Ru P C H                                                                           10.41   6.24 67.95  5.73                                                          10.57  6.48 67.84  5.48                                                           51.07                                                                              0.28 (d, 6H) 0.62 (d, 6H)                                                     1.20-1.35 (m, 2H) 2.20-2.30                                                   (m, 2H) 2.95 (s, 4H)                                                          6.10-7.90 (m, 32H)                17   Ru((-)-BINAP)(O.sub.2 C(CH.sub.2).sub.7 CH.sub.3).sub.2                                            Ru    9.41                                                                              9.73                                                                             64.25                                                                              0.80 (t, 6H)                           (for C.sub.62 H.sub.66 O.sub.4 P.sub.2 Ru)                                                         P     5.61                                                                              5.97    0.84-1.35 (m, 24H)                                          C    72.29                                                                             71.93    1.92-2.11 (m, 4H)                                           H     6.87                                                                              6.41    6.46-7.90 (m,                     __________________________________________________________________________                                                32H)                          

USE EXAMPLE 1

A 200 ml-volume autoclave was charged with 62 g (0.4 mol) of geranioland 75 ml of oxygen-free methanol, and 112 mg (0.13 mmol) ofRu((-)--BINAP)(O₂ CCH₃)₂ as prepared in Example 1 was added theretounder a nitrogen stream to effect hydrogenation at 20° C. for 27 hoursunder a hydrogen pressure of 30 kg/cm². After the solvent was distilledoff, the residue was subjected to distillation to obtain 61.5 g of afraction having a boiling point of 108° C./10 mmHg. The resultingfraction was found to contain 98.9% of citronellol by gas chromatography(silica capillary column "OV-101" manufactured by Gasukuro Kogyo Inc.;diameter: 0.25 mm; length: 25 m). The gas chromatography was carried outby increasing the temperature from 100° to 250° C. at a rate of 3°C./min. Optical Rotation, [α]_(D) ²⁵ +4.96° (c=31, chloroform).

The resulting citronellol was led to citronellic acid by Jones'oxidation, which was then converted to its amide usingR-(+)-(1-naphthyl)ethylamine. The amide was subjected to analysis ofdiastereomers by high performance liquid chromatography (column:Nucleosil 100-3 produced by Chemco Co., Ltd.; diameter: 4.6 mm; length:300 mm; eluent: hexane/diethyl ether=7:3 by volume; flow rate: 1 ml/min;detection wavelength: UV 254 nm). As a result, it was found that thestarting alcohol was a mixture comprising 97.45% of (R)-(+)-citronelloland 2.55% of (S)-(-)-citronellol. Therefore, the optical yield of thisreaction was 94.9%ee.

USE EXAMPLES 2 TO 17

In the same manner as in Use Example 1, geraniol was subjected toasymmetric hydrogenation by using each of the ruthenium-phosphinecomplexes of the invention as shown in Table 2. The results obtained arealso shown in Table 2.

In Table 2, the abbreviations used have the same meanings as describedabove.

                                      TABLE 2                                     __________________________________________________________________________    Use                      Substrate/                                                                          Reaction Conditions                                                                         Reaction Results                 Ex-                      Catalyst                                                                            Hydrogen                                                                            Tem-    Con-                                                                              Asymmetric                                                                           Selectivity           ample                    Molar Pressure                                                                            perature                                                                           Time                                                                             version                                                                           Yield  to Citronellol        No. Complex              Ratio (kg/cm.sup.2)                                                                       (°C.)                                                                       (hr)                                                                             (%) (%)    (%)                   __________________________________________________________________________    2   Ru((-)-(BINAP)(O.sub.2 CCF.sub.3).sub.2                                                            50000/1                                                                             30    20   14 98.6                                                                              95.5   99.4                  3   Ru((-)-TBINAP).sub.2 (O.sub.2 CCH.sub.3).sub.2                                                     5000/1                                                                              30    20   3.7                                                                              98.7                                                                              98.5   99.4                  4   Ru((-)-BINAP)(O.sub.2 Ct-Bu).sub.2                                                                 1000/1                                                                              30    20   50 99.3                                                                              97.1   96.9                  5   Ru((-)-BINAP)(O.sub.2 CPh).sub.2                                                                   5000/1                                                                              30    20   8  97.2                                                                              97.5   99.4                  6   Ru((-)-TBINAP)(O.sub.2 CCH.sub.3).sub.2                                                            10000/1                                                                             30    20   8  96.2                                                                              98.8   99.8                       ##STR9##            5000/1                                                                              30    20   40 97.2                                                                              96.1   99.7                  8   Ru((-)-BINAP)(O.sub.2 CCF.sub.3).sub.2                                                             50000/1                                                                             30    20   12 99.5                                                                              97.0   99.8                  9   Ru((-)-t-BuBINAP)(O.sub.2 CCH.sub.3).sub.2                                                         10000/1                                                                             30    20   5  96.3                                                                              96.3   99.7                  10  Ru-((+)-amino BINAP)(O.sub.2 CCH.sub.3).sub.2                                                      5000/1                                                                              30    20   48 98.2                                                                              94.1   98.7                  11  Ru-((+)-acetylamino BINAP)-                                                                        5000/1                                                                              30    20   57 95.6                                                                              95.2   99.2                      (O.sub.2 CCH.sub.3).sub.2                                                 12  Ru((+)-sulfonated BINAP)-                                                                          500/1 30    20   32 54.5                                                                              95.0   99.3                      (O.sub.2 CCH.sub.3).sub.2                                                 13                                                                                 ##STR10##           5000/1                                                                              30    20   4.5                                                                              98.5                                                                              97.5   97.5                  14  Ru((-)-TBINAP).sub.2 (O.sub.2 CCF.sub.3).sub.2                                                     50000/1                                                                             30    20   30 99.6                                                                              98.2   99.5                  15                                                                                 ##STR11##           5000/1                                                                              30    20   23 53.6                                                                              99.7   99.6                  16                                                                                 ##STR12##           5000/1                                                                              30    20   50 85.7                                                                              99.7   99.5                  17  Ru((-)-BINAP)(O.sub.2 C(CH.sub.2).sub.7 CH.sub.3).sub.2                                            2000/1                                                                              30    20   50 97.8                                                                              97.5   98.9                  __________________________________________________________________________

As described above, the present invention provides a novelruthenium-phosphine complex in which carboxylic groups are bonded tometallic ruthenium. The ruthenium-phosphine complex according to thisinvention exhibits superior performances as a catalyst for variousorganic syntheses, and particularly for asymmetric hydrogenation, toaccomplish satisfactory results in selective hydrogenation of olefinsand catalytic activity from the industrial viewpoint. In addition, thecomplex of the invention can be prepared at a lower cost as comparedwith the conventoinal rhodium catalysts, thus making a greatcontribution to reduction of price of products.

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made therein withoutdeparting from the spirit and scope thereof.

What is claimed is:
 1. A ruthenium-phosphine complex represented byformula ##STR13## wherein X represents a hydrogen atom, an amino group,an acetylamino group, or a sulfo group; R represents a hydrogen atom ora lower alkyl group; R₁ and R₂ each represents an alkyl group, ahalogenated lower alkyl group, a phenyl group, a phenyl groupsubstituted with a lower alkyl group, an α-aminoalkyl group, or anα-aminophenylalkyl group, or R₁ and R₂ are taken together to form analkylene group; and n represents 1 or
 2. 2.[2,2'-Bis(diphenylphosphino)-1,1'-binaphthyl]ruthenium-diacetate,according to claim
 1. 3.[2,2'-Bis(diphenylphosphino)-1,1'-binaphthyl]ruthenium-ditrifluoroacetate,according to claim
 1. 4.Bis[2,2'-bis(di-p-tolylphosphino)-1,1'-binaphthyl]ruthenium-diacetate,according to claim
 1. 5.Bis[2,2'-bis(di-p-tolylphosphino)-1,1'-binaphthyl]ruthenium-ditrifluoroacetate,according to claim 1.